CN102482170B

CN102482170B - An encapsulated particle

Info

Publication number: CN102482170B
Application number: CN201080027871.2A
Authority: CN
Inventors: D·C·门特
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-06-24
Filing date: 2010-06-23
Publication date: 2014-10-08
Anticipated expiration: 2030-06-23
Also published as: SG176615A1; JP2012530600A; US20100326152A1; US8303680B2; EP2445851A1; KR20130001205A; KR101855533B1; MX2011013426A; CN102482170A; JP5968219B2; CA2763942A1; CA2763942C; WO2010149713A1

Abstract

An encapsulated particle comprises a core particle and a polyurethane layer disposed about the core particle. The core particle can be various particles, such as fertilizer, biocides, flame retardants, seeds, etc. The polyurethane layer comprises the reaction product of an isocyanate component and an isocyanate-reactive component. The isocyanate-reactive component comprises a graft polyol having a continuous phase and polymeric particles. A method of forming the encapsulated particle comprises the steps of providing the core particle, applying the isocyanate and isocyanate-reactive components to the core particle, and reacting the isocyanate and isocyanate-reactive components to form the polyurethane layer. The encapsulated particle has excellent physical properties, such as increased water repellency, resiliency and shelf life.

Description

The particle of sealing

Invention field

The present invention relates generally to a kind of particle of sealing, especially relate to the encapsulated particles that comprises nuclear particle and be positioned at described nuclear particle around and comprise isocyanate component and the layer of polyurethane of the reaction product of isocyanate-reactive component containing graft polyol.

Description of Related Art

Encapsulated particles, for example release and release control fertilizer is known in agriculture field.This class encapsulated particles conventionally comprises and is positioned at nuclear particle, is generally fertilizer as urea one or more layer of polyurethane around.The thickness of layer of polyurethane and integrity have limited the dissolution rate of described encapsulated particles, thereby especially nuclear particle degraded is discharged into the speed in the soil of moisture content by self as " useful load ".

Unfortunately, many conventional encapsulated particles have inhomogenous layer of polyurethane thickness, and this causes dissolution rate to be accelerated.Known as agriculture field, the dissolution rate of this quickening causes waste and phytotoxicity, the i.e. toxic action of fertilizer to plant-growth.In addition, many conventional encapsulated particles have the layer of polyurethane that has integrity issue because layer of polyurethane comprises defect as crackle, concave point, depression etc.When the layer of polyurethane that comprises these defects is positioned at nuclear particle around time, described crackle, concave point and/or depression allow that water and other liquid infiltrate in layer of polyurethane, thereby contact too early and dissolve nuclear particle.In order to overcome this class defect, conventionally must make a plurality of layer of polyurethane around nuclear particle, this production method that causes forming encapsulated particles is consuming time and expensive.Another aspect, because layer of polyurethane lacks, enough consistency and elasticities are easy to break many conventional encapsulated particles.This breaking reduced the storage time of encapsulated particles, and causes the waste of encapsulated particles in storage, processing and use procedure.EP 867422 discloses the coated particle of the film with coated fertilizer particle.This film comprises urethane resin and particle diameter is water-fluid absorbency particle of 1-200 μ m.

Therefore, still exist provide there is the moistureproofness of improvement, the hydrophobicity of the swell-resistant of improvement, improvement, the chance of the elasticity of the production cost of reduction and improvement and the encapsulated particles of toughness.Also there is the chance that the encapsulated particles with prolongation and more predictable dissolution rate is provided.Also there is the chance that the method that forms this class encapsulated particles is provided.

Summary of the invention and advantage

Encapsulated particles comprises nuclear particle and is positioned at nuclear particle layer of polyurethane around.The reaction product that described layer of polyurethane comprises isocyanate component and isocyanate-reactive component.Described isocyanate-reactive component comprises the graft polyol with external phase and polymer beads.The method that forms described encapsulated particles comprises the steps: to provide nuclear particle, isocyanate component and isocyanate-reactive component is applied on nuclear particle, and makes described isocyanate component and isocyanate-reactive component reaction to form layer of polyurethane.

The invention provides the unique combination of isocyanic ester and isocyanate-reactive component.The graft polyol of isocyanate-reactive component is given moistureproofness, the swell-resistant of improvement, the toughness of the production cost of reduction and improvement of encapsulated particles to improve.The layer of polyurethane of encapsulated particles provides that extend and more predictable dissolution rate for encapsulated particles.The common acquisition of method that the present invention forms encapsulated particles is positioned at nuclear particle even, complete and flawless layer of polyurethane around.Equally, can use and be positioned at nuclear particle thinner and more cheap layer of polyurethane around.In addition, the particle of sealing and component thereof are shelf-stable, thereby allow that encapsulated particles and component thereof more effectively store and application subsequently.

Accompanying drawing summary

When considering together with accompanying drawing, by will easily and understanding better other advantages of the present invention with reference to below describing in detail, in described accompanying drawing simultaneously:

Fig. 1 is the cross section of encapsulated particles of the present invention;

Fig. 2 is the figure of the dissolution rate of explanation comparative example;

Fig. 3 is another figure of the dissolution rate of explanation comparative example; With

Fig. 4 is the figure of the dissolution rate of explanation inventive embodiments of the present invention.

Detailed Description Of The Invention

With reference to accompanying drawing (wherein in whole several views, the part that identical numeral is identical), encapsulated particles of the present invention is conventionally with 10 expressions.Encapsulated particles 10 comprises nuclear particle 12.In certain embodiments, nuclear particle 12 comprises fertilizer.Conventionally, fertilizer is selected from nitrogen, phosphoric acid salt, potash, sulphur and combination thereof.For the present invention, suitable fertilizer can be commercially available from a plurality of suppliers known to the person skilled in the art.

In one embodiment, described fertilizer is nitrogen base.For the present invention, the example of suitable nitrogen base manure material comprises anhydrous ammonia, urea, ammonium nitrate, urea-ammonium nitrate (urea ammoniumnitrate), calcium ammonium nitrate and combination thereof.In another embodiment, described fertilizer is phosphate base.For the present invention, the example of suitable phosphate base fertilizer comprises phosphoric acid, mono phosphoric acid ester ammonium, ammonium polyphosphate, phosphoric acid ammonium sulfate and combination thereof.In yet another embodiment, described fertilizer is potash base.For the present invention, the example of suitable potash base manure material comprises potash, ammonium nitrate and combination thereof.In yet another embodiment, described fertilizer is sulfenyl.For the present invention, the example of suitable sulfenyl fertilizer comprises ammonium sulfate, sulfuric acid and combination thereof.

In other embodiments, nuclear particle 12 comprises biocides.For the present invention, the example of biocides comprises weedicide, sterilant, mycocide and combination thereof.Should be understood that, can use the alternative form of nuclear particle 12 yet, is not the nuclear particle 12 of fertilizer or biocides, as fire retardant.Other nuclear particles 12 that are suitable for the object of the invention include but not limited to that bulb and seed are as grass seed, flower seed etc.

It is about 75-approximately 99 weight parts that nuclear particle 12 be take based on 100 weight part encapsulated particles 10 conventionally, is more typically about 90-approximately 99 weight parts, and the amount that is generally about 96-approximately 98 weight parts is most present in described encapsulated particles 10.Should be understood that, encapsulated particles 10 can comprise the arbitrary combination of two or more above-mentioned nuclear particles 12.In these embodiments, nuclear particle 12 can be including but not limited to the mixture of nuclear particle composition, the independent subparticle of nuclear particle 12 and/or the layer of different IPs particulate composition.For example, nuclear particle 12 can comprise urea-containing kernel, and described kernel has the outer core that is positioned at this kernel around and comprises sulphur.Conventionally, nuclear particle 12 is anhydrous, or at least on its outermost surface for anhydrous (being that nuclear particle 12 is done), in the production of encapsulated particles 10 and/or storage process, react too early and/or degrade preventing.

Nuclear particle 12 can have various size and shape.Nuclear particle 12 is spherical conventionally substantially, and it has approximately 5 millimeters of about 0.1-(mm), is more typically the about 2.5mm of about 0.1-, is generally the mean diameter of the about 1mm of about 0.25-most.Should be understood that, also can use the nuclear particle 12 of other sizes and/or shape, for example irregular, ellipse or platy shaped particle.In one embodiment, nuclear particle 12 is quite large.For example, nuclear particle 12 can be conventional tree sour jujube shape, so that the tree sour jujube (not shown) of encapsulated particles 10 for sealing.

Encapsulated particles 10 further comprises and is positioned at nuclear particle 12 layer of polyurethane 14 around.For the present invention, should be understood that, term " is positioned at ... contain nuclear particle 12 around " by layer of polyurethane 14 parts and cover the two completely.Conventionally, nuclear particle 12 is covered by layer of polyurethane 14 completely, protects thus nuclear particle 12 in order to avoid is exposed under envrionment conditions, for example, in order to avoid be exposed under moisture too early.Layer of polyurethane 14 conventionally has and is similar to conventional encapsulated layer as the mean thickness of the thickness of conventional fertilizer encapsulated layer, about 50-approximately 200 μ m (micron) for example, more generally about 100-150 μ m, the thickness of the most common about 125-approximately 150 μ m.Should be understood that, depend on that one or more desired properties are as the dissolution rate of encapsulated particles 10, layer of polyurethane 14 can form different thickness.

The reaction product that layer of polyurethane 14 comprises isocyanate component and isocyanate-reactive component.Described isocyanate component is generally the polyisocyanates with two or more isocyanate functional groups (NCO).For the present invention, suitable polyisocyanates includes but not limited to conventional aliphatic, alicyclic, araliphatic and aromatic isocyanate.In certain embodiments, described isocyanate component is selected from '-diphenylmethane diisocyanate (MDI), polymerization diphenylmethane diisocyanate (PMDI) and combination thereof.Polymerization diphenylmethane diisocyanate in this area also referred to as polymethylene polyphenylene(poly)isocyanate.For the present invention, the example of other suitable isocyanic ester includes but not limited to tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), naphthalene diisocyanate (NDI) and combination thereof.

In certain embodiments, described isocyanate component is isocyanate-terminated prepolymer.As understood in polyurethane field, isocyanate-terminated prepolymer is the reaction product of isocyanic ester and polyvalent alcohol and/or polyamine.Described isocyanic ester can be the isocyanic ester of the known any type of the those of ordinary skill of polyurethane field, for example one of above-mentioned polyisocyanates.If for the preparation of isocyanate-terminated prepolymer, described polyvalent alcohol is selected from ethylene glycol, glycol ether, propylene glycol, dipropylene glycol, butyleneglycol, glycerine, TriMethylolPropane(TMP), trolamine, tetramethylolmethane, sorbyl alcohol and combination thereof conventionally.If for the preparation of isocyanate-terminated prepolymer, described polyamine is selected from quadrol, tolylene diamine, diaminodiphenylmethane and polymethylene polyphenylamine, amino alcohol and combination thereof conventionally.The example of suitable amino alcohol comprises thanomin, diethanolamine, trolamine and combination thereof.Should be understood that, described isocyanate-terminated prepolymer can be in above-mentioned polyvalent alcohol and/or polyamine two or more be combined to form.

Described isocyanate component also can be modified isocyanate, for example carbodiimide, allophanate, isocyanuric acid ester and biuret.For the present invention, other suitable isocyanic ester comprise those described in U.S.'s publication 2005/0266245 of Mente etc., by reference its whole disclosures are incorporated herein.

For the present invention, the specific examples of suitable isocyanate component can be with trade(brand)name by BASF Corporation of Florham Park, NJ is commercially available, for example m, mI, m20, m20SB, m20HB and m20FB isocyanic ester.

It is about 25-approximately 1 weight part that layer of polyurethane 14 be take the particle 10 of sealing based on 100 weight parts conventionally, is more typically about 10-approximately 1 weight part, and the amount that is generally about 4-approximately 2 weight parts is most present in this particle of sealing 10.Generally speaking, the invention provides with respect to the encapsulated particles of prior art and use material still less, for example, use isocyanate component still less.

Described isocyanate component conventionally has and is suitable for this isocyanate component to be applied on nuclear particle 12 by ad hoc fashion, for example by spraying, cloud (fogging) thereby and/or atomization isocyanate component isocyanate component is applied to the viscosity on nuclear particle 12.It is about 10-approximately 5 according to ASTM D2196 that described isocyanate component has conventionally at 25 ℃, and 000mPas (cps), is more typically about 25-approximately 2, and 500cps is generally the viscosity of the about 200cps of about 50-most.No matter which kind of uses apply technology, the viscosity of isocyanate component should be enough to fully apply nuclear particle 12.

In certain embodiments, described isocyanate component has about 1-approximately 5, is more typically about 1.5-approximately 4, is generally the nominal functionality of about 2.0-approximately 2.7 most.In certain embodiments, it is about 20-approximately 50 % by weight that described isocyanate component has based on this isocyanate component of 100 weight parts, is more typically about 25-approximately 40 % by weight, is generally the NCO content of about 30-approximately 33 % by weight most.Above-mentioned NCO content provides the polymer cross-linking density of the isocyanate component that contributes to form zero defect layer of polyurethane 14 conventionally, and provides isocyanate component that per unit mass has more chemical bonds to improve cost efficiency.

It is about 1-approximately 50 weight parts that described isocyanate component be take based on 100 weight part reaction product conventionally, be more typically about 1-approximately 25 weight parts, still be more typically about 1-approximately 15 weight parts, be generally about 5-approximately 10 weight parts most, the amount that is still generally most approximately 7 weight parts exists.Should be understood that, isocyanate component can comprise the arbitrary combination of above-mentioned isocyanic ester and/or isocyanate-terminated prepolymer.

Described isocyanate-reactive component comprises graft polyol.In one embodiment, graft polyol is polymer polyatomic alcohol.In other embodiments, described graft polyol is selected from polyureas (polyharnstoff (PHD)) polyvalent alcohol, polyisocyanate polyaddition (PIPA) polyvalent alcohol and combination thereof.Should be understood that, described isocyanate-reactive component can comprise the arbitrary combination of above-mentioned graft polyol.In certain embodiments, described isocyanate-reactive component also can comprise other components, comprises auxiliary polyvalent alcohol and/or other standards urethane resin component, and this will below be further described.In another embodiment, described isocyanate-reactive component consists of graft polyol.

Graft polyol also can be described as graft polyol dispersion or graft polyol polymkeric substance in the art.Graft polyol is that the those of ordinary skill of polyurethane field is known, and comprise product, by the polymer beads 16 obtaining as styrene monomer and/or acrylonitrile monemer and macromonomer as one or more vinyl monomers of polyether glycol situ polymerization at polyvalent alcohol.In one embodiment, described isocyanate-reactive component is styrene-acrylonitrile graft polyol.PHD polyvalent alcohol forms by making vulcabond react to obtain stable polyureas particle dispersion with diamines at polyvalent alcohol situ conventionally.PIPA polyalcohols is similar to PHD polyvalent alcohol, and difference is that dispersion is conventionally by making vulcabond and alkanolamine (but not diamines) reaction in－situ form with the polyurethane dispersions obtaining in polyvalent alcohol.Should be understood that, the invention is not restricted to prepare any ad hoc approach of graft polyol.

Described isocyanate-reactive component comprises external phase.The external phase of isocyanate-reactive component conventionally not with isocyanate component miscible, this reactive group that has improved polymer beads 16 is as the fraction of coverage of hydroxy functional group (OH).When reaction-ity group reaction, these reactive groups can further cause being cross-linked in layer of polyurethane 14.Polymer beads 16 will below be further described.In certain embodiments, as described above, external phase and polymer beads 16 all can react with isocyanate component.These embodiments will below described in more detail.

The external phase of described isocyanate-reactive component comprises polyvalent alcohol conventionally.Described polyvalent alcohol is conventionally also illustrative like that for being used to form the polyvalent alcohol of graft polyol as described above.This polyvalent alcohol can be described as " carrier " polyvalent alcohol in the art; Yet, except carrier polyol or substitute described carrier polyol, also can use the polyvalent alcohol clearly separating with polymer beads 16.Described polyvalent alcohol has at least two hydroxy functional groups (OH) that can react with isocyanate component conventionally.Described polyvalent alcohol also can with above to isocyanate-terminated prepolymer describe and illustrative polyvalent alcohol identical or different.Described isocyanate-reactive component can comprise polyester polyol, polyether glycol and combination thereof.In addition, described polyvalent alcohol can be selected from but be not limited to aliphatic polyol, alicyclic polyol, aromatic polyol, heterocycle family polyvalent alcohol and combination thereof.The example more specifically of suitable polyvalent alcohol is selected from but is not limited to glycerine, propylene glycol, the polyvalent alcohol that sucrose causes, the polyvalent alcohol that sucrose/glycerol causes, polyvalent alcohol and the combination thereof that TriMethylolPropane(TMP) causes.In certain embodiments, described polyvalent alcohol is (or derived from) " natural " oil, for example Semen Maydis oil, Oleum Gossypii semen, castor-oil plant wet goods.In these embodiments, conventionally use Viscotrol C.In these embodiments, the external phase of isocyanate-reactive component comprises Viscotrol C conventionally.It is very hydrophobic that Viscotrol C is generally, and have high hydroxyl value, and this is useful for the present invention.Viscotrol C also can be easily commercially available by a plurality of suppliers.Use natural oil to utilize the possible of natural and continuable raw material as Viscotrol C provides.

In certain embodiments, described polyvalent alcohol is hydrophobicity polyvalent alcohol.In specific embodiments, described polyvalent alcohol is hydrophobicity polyether glycol.In another embodiment, described polyvalent alcohol is hydrophobicity polyester polyol.Hydrophobicity polyvalent alcohol contains oxyalkylene.In these embodiments, the oxyalkylene that hydrophobicity polyvalent alcohol has conventionally based on this hydrophobicity polyvalent alcohol of 100 weight parts is about 0-approximately 50 weight parts, is more typically about 2-approximately 20 weight parts, is generally the ethylene oxide (EO) of about 5-approximately 15 weight parts most.In other embodiments, it is at least 60 weight parts that hydrophobicity polyvalent alcohol has based on 100 weight part oxyalkylenes conventionally, is more typically at least 70 weight parts, is generally the propylene oxide (PO) of at least 80 weight parts most.Therefore, in these embodiments, hydrophobicity polyvalent alcohol is the polyvalent alcohol that is rich in propylene oxide, and this gives described hydrophobicity polyvalent alcohol with hydrophobicity, and the layer of polyurethane 14 of therefore further giving encapsulated particles 10 is with hydrophobicity.

In certain embodiments, the oxyalkylene of described hydrophobicity polyvalent alcohol comprises the mixture of ethylene oxide and propylene oxide.In another embodiment, the oxyalkylene of described hydrophobicity polyvalent alcohol only comprises propylene oxide, and described hydrophobicity polyvalent alcohol does not comprise other oxyalkylenes as ethylene oxide.In certain embodiments, the oxyalkylene that described hydrophobicity polyvalent alcohol comprises other types known in polyurethane field, for example, with propylene oxide, and oxybutylene (BO) optional and ethylene oxide combination.The oxyalkylene of hydrophobicity polyvalent alcohol can be arranged with various configurations, for example random (mixing) configuration, block configuration, end-blocking configuration or its combination.For example, in one embodiment, the hybridization compound that described hydrophobicity polyvalent alcohol comprises ethylene oxide and propylene oxide.

In certain embodiments, described hydrophobicity polyvalent alcohol ethylene oxide-capped.It is about 5-approximately 25 weight parts that described hydrophobicity polyvalent alcohol has based on this hydrophobicity polyvalent alcohol of 100 weight parts conventionally, is more typically about 5-approximately 20 weight parts, is generally the ethylene oxide end of about 10-approximately 15 weight parts most.Should be understood that, in certain embodiments, ethylene oxide may only exist only in ethylene oxide end; Yet in other embodiments, ethylene oxide also can be with propylene oxide and is optionally present in the oxyalkylene of hydrophobicity polyvalent alcohol together with oxybutylene with other oxyalkylenes.Conventionally, for the present invention, preferably hydrophobicity polyvalent alcohol has the propylene oxide content of raising, thereby gives the hydrophobicity of the layer of polyurethane 14 of encapsulated particles 10 with raising.

For the present invention, suitable hydrophobicity polyvalent alcohol includes but not limited to polyether glycol, the polyether glycol that TriMethylolPropane(TMP) causes, the polyether glycol of propylene glycol initiation and polyether glycol and the combination thereof that sucrose causes that glycerine causes.In one embodiment, described hydrophobicity polyvalent alcohol is the polyether glycol that glycerine causes.In another embodiment, described hydrophobicity polyvalent alcohol is the polyester polyol that glycerine causes.The oxyalkylene of hydrophobicity polyvalent alcohol is conventionally from the corresponding initiator part chain extension of this hydrophobicity polyvalent alcohol.

As mentioned above, described isocyanate-reactive component comprises polymer beads 16.This polymer beads 16 can be called the discontinuous phase of isocyanate-reactive component in the art.Polymer beads 16 has large size conventionally due to its macromonomer component, and polymer beads 16 has micron-scale or large size more, as micron order or larger diameter.In certain embodiments, the mean diameter of polymer beads 16 is about 0.1-approximately 10 μ m, is more typically about 0.1-approximately 1.5 μ m.In other embodiments, the mean diameter of polymer beads 16 is for being less than 0.1 μ m, and this makes isocyanate-reactive component have nanometer polymerization composition granule 16.Should be understood that, polymer beads 16 can comprise nanometer and micron order (or less and/or larger) particle.

As mentioned above, polymer beads 16 comprises the reaction product of the monomer that is selected from following group conventionally: styrenic is as the ester of alpha-methyl styrene, vinyl cyanide, vinylformic acid and methacrylic acid, olefinically unsaturated nitriles, amine, acid amides and combination thereof.In certain embodiments, as mentioned above, polymer beads 16 relates to macromonomer, as has the further reaction of the polyvalent alcohol of degree of unsaturation (for example one or more ethylenic groups), and this allows the chemistry of polymer beads 16 to mix.In these embodiments, it is believed that polymer beads 16 can be layer of polyurethane 14 and provides crosslinked, due to the OH group that the reactive group being connected on polymer beads 16 is given as polyvalent alcohol, it can react with isocyanate component.

In one embodiment, polymer beads 16 comprises styrene-acrylonitrile (SAN) multipolymer, and as understood in the art, it is the reaction product of styrene monomer and acrylonitrile monemer.The styrene/acrylonitrile weight ratio of san copolymer is generally approximately 30: 70-approximately 70: 30, be more typically approximately 40: 60-approximately 60: 40, still be more typically approximately 45: 55-approximately 60: 40, is generally approximately 50 most: 50-approximately 60: 40, is still generally most approximately 55: 45-approximately 60: 40.In one embodiment, the styrene/acrylonitrile weight ratio of san copolymer is approximately 66.7: 33.3.In another embodiment, polymer beads 16 is urea, and it is that amine monomers and isocyanate functional group (NCO) are as the reaction product of the NCO group of vulcabond.In yet another embodiment, polymer beads 16 is carbamate, and it is that alcohol monomer and NCO group are as the reaction product of the NCO group of vulcabond.

It is about 5-approximately 70 weight parts that polymer beads 16 be take based on 100 weight part isocyanate-reactive components conventionally, is more typically about 15-approximately 55 weight parts, and the amount that is generally about 25-approximately 50 weight parts is most present in this isocyanate-reactive component.In one embodiment, polymer beads 16 amount that to take based on 100 weight part isocyanate-reactive components be approximately 65 weight parts is present in this isocyanate-reactive component.Generally speaking, the amount of raising polymer beads 16 can improve the water-repellancy of the layer of polyurethane 14 of encapsulated particles 10.Also it is believed that for the encapsulated particles of prior art, polymer beads 16 is given the elasticity of encapsulated particles 10 to improve.

The molecular weight of graft polyol is generally about 400-approximately 20,000, is more typically about 500-approximately 10,000, is still more typically about 600-approximately 5,000, is generally about 700-approximately 3,000 most.In one embodiment, the molecular weight of graft polyol is approximately 730.In another embodiment, the molecular weight of graft polyol is approximately 3,000.

For the present invention, graft polyol that other are suitable and preparation method thereof comprises United States Patent (USP) 4,522,976, Grace etc.; 5,093,412, Mente etc.; 5,179,131, Wujcik etc.; 5,223,570, Huang etc.; 5,594,066, Heinemann etc.; 5,814,699, Kratz etc.; 6,034,146, Falke etc.; 6,103,140, Falke etc.; 6,352,658, Chang etc.; 6,432,543, Harrison etc.; 6,472,447, Lorenz etc.; 6,649,107, Harrison etc.; With those described in 7,179,882, Adkins etc., by reference its disclosure is all incorporated herein.

For the present invention, the specific examples of suitable graft polyol can be with trade(brand)name by BASF Corporation of Florham Park, NJ is commercially available, for example 1365, 4600, 4650, 4800, 4815, 4830 Hes 4850 graft polyols.Should be understood that, isocyanate-reactive component can comprise the arbitrary combination of two or more above-mentioned graft polyols.Details about graft polyol are described in The Polyurethanes Handbook (David Randall & Steve Lee volume, JohnWiley & Sons, Ltd.2002) the 104th and 105 pages in, its full content is incorporated herein.For the present invention, the example of the appropriate method of preparation graft polyol dispersion is the Raolical polymerizable of vinyl cyanide, vinylbenzene and polyether glycol macromonomer, wherein said components has at least one olefin group separately, described polyether glycol further comprises at least one hydroxyl, and described reaction initiator as the existence of radical polymerization initiator under and optionally in the existence of extra polyvalent alcohol that can be identical or different with above-mentioned polyether glycol, carry out.

Described isocyanate-reactive component conventionally has and is suitable for this isocyanate-reactive component to be applied on nuclear particle 12 by ad hoc fashion, for example, by spraying, cloud and/or atomization isocyanate-reactive component, this isocyanate-reactive component is applied to the viscosity on nuclear particle 12.It is about 100-approximately 10 according to ASTM D2196 that isocyanate-reactive component has conventionally at 25 ℃, and 000mPas (cps), is more typically about 500-approximately 5,000cps, the most common about 500-approximately 3, the viscosity of 000cps.No matter which kind of adopts apply technology, the viscosity of isocyanate-reactive component should be enough to apply fully nuclear particle 12.

It is about 99-approximately 50 weight parts that isocyanate-reactive component be take based on 100 weight part reaction product conventionally, be more typically about 99-approximately 75 weight parts, still be more typically about 99-approximately 85 weight parts, be generally about 95-approximately 90 weight parts most, the amount that is still generally most approximately 93 weight parts exists.Should be understood that, isocyanate-reactive component can comprise the arbitrary combination of above-mentioned polyvalent alcohol, polymer beads and/or graft polyol.

Isocyanic ester and isocyanate-reactive component can be present in layer of polyurethane 14 with Different Weight ratio.Conventionally, described graft polyol must exist as the elastic amount of encapsulated particles 10 to be enough to give layer of polyurethane 14 hydrophobicitys and other physicalies as herein described.

Conventionally described isocyanic ester and isocyanate-reactive component being take based on the respective reaction reactive site of isocyanic ester and isocyanate-reactive component is as understood in the art about 1.5-1, be more typically about 1.25-1, the ratio that is generally about 1.1-1 is most applied on nuclear particle 12.This ratio can be described as isocyanate index in polyurethane field, and this is known in those skilled in the art.

As mentioned above, described reaction can further comprise the auxiliary polyvalent alcohol being different from as the polyvalent alcohol of (or for) isocyanate-reactive component.Be suitable for use as the polyvalent alcohol of auxiliary polyvalent alcohol as isocyanate-terminated prepolymer described and illustration above.Described auxiliary polyvalent alcohol can be used for various objects.For example, the reactive functional groups that the auxiliary polyvalent alcohol with higher functionality (with respect to the polyvalent alcohol of graft polyol) can be used for providing extra is for reacting with isocyanate component, or auxiliary polyvalent alcohol can be used for improving or reducing the viscosity of isocyanate-reactive component.If use, auxiliary polyvalent alcohol can be used with difference amount.

Reaction product can further comprise binder component.If use, binder component is selected from releasing agent, catalyzer, filler, softening agent, stablizer, linking agent, chainextender, chain terminator, air release agent, wetting agent, surface-modifying agent, moisture scavenger, siccative, viscosity-depression agent, toughener, tinting material, antioxidant, compatibilizing agent, UV light stabilizing agent, thixotropic agent, antiaging agent, lubricant, coupling agent, solvent, rheology promotor, thickening material, static inhibitor and combination thereof conventionally.If use, described binder component can exist with difference amount.Should be understood that, if use, binder component can comprise the arbitrary combination of above-mentioned additive.

In certain embodiments, described binder component comprises catalyst component.In one embodiment, described catalyst component comprises tin catalyst.For the present invention, suitable tin catalyst comprises the tin of organic carboxyl acid (II) salt, for example tin acetate (II), stannous octoate (II), thylhexoic acid tin (II) and tin laurate (II).In one embodiment, organo-metallic catalyst comprises dibutyl tin dilaurate, and it is dialkyl tin (IV) salt of organic carboxyl acid.For the present invention, the specific examples of suitable organo-metallic catalyst as dibutyl tin dilaurate can be with trade(brand)name by Air Products andChemicals, Inc.of Allentown, PA is commercially available.Organo-metallic catalyst also can comprise dialkyl tin (IV) salt of other organic carboxyl acids, for example oxalic acid two fourth tin, dibutyltin maleate and the pungent tin of oxalic acid two.

For the present invention, the example of other suitable catalyst comprises iron(ic) chloride (II); Zinc chloride; Lead octoate 36; Three (dialkyl aminoalkyl)-s-Hexahydrotriazines, comprise three (N, N-dimethylamino-propyl)-s-Hexahydrotriazine; Tetraalkylammonium hydroxide, comprises tetramethyl ammonium hydroxide; Alkali metal hydroxide, comprises sodium hydroxide and potassium hydroxide; Alkali metal alcoholates, comprises sodium methylate and potassium isopropoxide; And an alkali metal salt with the longer chain fatty acid of 10-20 carbon atom and/or OH side group.

For the present invention, the catalyzer that other are suitable, particularly other examples of catalyst for trimerization comprise N, N, N-dimethylamino-propyl Hexahydrotriazine, potassium, potassium acetate, N, N, N-trimethylammonium Isopropylamine/formate and combination thereof.The specific examples of suitable catalyst for trimerization can be with trade(brand)name by Air Products and Chemicals, Inc. is commercially available.

For the present invention, the catalyzer that other are suitable, other examples of tertiary amine catalyst particularly comprise dimethylaminoethanol, dimethylamino ethoxy ethanol, triethylamine, N, N, N ', N '-Tetramethyl Ethylene Diamine, N, N-dimethylaminopropylamine, N, N, N ', N ', N " pentamethyl-dipropylenetriamine, three (dimethylamino-propyl) amine, N, N-lupetazin, tetramethyl-imino-two (propylamine), dimethyl benzyl amine, Trimethylamine 99, trolamine, N, N-diethylethanolamine, N-Methyl pyrrolidone, N-methylmorpholine, N-ethylmorpholine, two (2-dimethylaminoethyl) ether, N, N-dimethylcyclohexylam,ne (DMCHA), N, N, N ', N ', N " five methyl diethylentriamine, 1, 2-methylimidazole, 3-(dimethylamino) propyl imidazole and combination thereof.The specific examples of suitable tertiary amine catalyst can be with trade(brand)name by AirProducts and Chemicals, Inc. is commercially available.

If use, catalyst component can be used with difference amount.Should be understood that, catalyst component can comprise the arbitrary combination of above-mentioned catalyzer.In certain embodiments, encapsulated particles 10 forms not existing under catalyzer.

In certain embodiments, binder component comprises tinting material if dyestuff and/or pigment are with coloured polyurethanes layer 14.Tinting material makes the integrity of layer of polyurethane 14 be able to visual assessment and various sale advantages can be provided.If use, tinting material can be used with difference amount.

Layer of polyurethane 14 does not basically contain water conventionally." do not basically contain " and mean in these embodiments, water with based on 100 weight part layer of polyurethane 14 for being not more than approximately 5 weight parts, be more typically and be not more than approximately 2.5 weight parts, be still more typically and be not more than approximately 1 weight part, be generally the amount existence that is similar to or equals 0 weight part most.If it is completely not moisture that those skilled in the art know layer of polyurethane 14, layer of polyurethane 14 is anhydrous.Conventionally optimization polyurethane layer 14 have on a small quantity or do not have water with prevent encapsulated particles 10 for example by softening, break or bond/agglomeration is to other adjacent encapsulated particles 10 or surface is upper and degrade too early.This degraded can cause too early release and the waste of nuclear particle 14.Depend on the concrete nuclear particle 12 that is used to form encapsulated particles 10, water also may be harmful to nuclear particle 14.

In certain embodiments, layer of polyurethane 14 does not basically contain wax, for example paraffin." do not basically contain " and mean in these embodiments, wax with based on 100 weight part layer of polyurethane 14 for being not more than approximately 5 weight parts, be more typically and be not more than approximately 2.5 weight parts, be still more typically and be not more than approximately 1 weight part, be generally the amount existence that is similar to or equals 0 weight part most.Layer of polyurethane 14 has on a small quantity or does not have wax conventionally to allow to form uniform layer of polyurethane 14, and this can infiltrate in layer of polyurethane 14 by anti-sealing.Yet, if with concrete component compatibility used, wax can be used in layer of polyurethane 14.Or or additionally, wax can be used as the additional coatings (not shown) on layer of polyurethane 14.

In certain embodiments, layer of polyurethane 14 comprise contiguous nuclear particle 12 isocyanate-reactive component concentration and away from the concentration of the isocyanate component of the concentration of nuclear particle 12 and contiguous isocyanate-reactive component.In other words, conventionally have concentration gradient in layer of polyurethane 14, wherein said concentration gradient has the innermost layer part 18 that mainly comprises isocyanate-reactive component and the outermost layer part 20 that mainly comprises isocyanate component.Can understand this concentration gradient with reference to Fig. 1.It is to be further understood that encapsulated particles 10 and concentration gradient are not drawn to scale in Fig. 1, its describe only for illustrative purpose.In these embodiments, layer of polyurethane 14 provides substantially covering uniformly nuclear particle 12, wherein the concentration of isocyanate component is given encasing articles 10 with elastic coating, and the concentration of isocyanate-reactive component is given the even coating of encapsulated particles 10 on nuclear particle 12.It is believed that concentration orientation is favourable, because isocyanate-reactive component (at first) " more tacky " for isocyanate component, and therefore stick to better in process of production on nuclear particle 12, and isocyanate component subsequently (after production) not with atmosphere in moisture react, thereby give hard external coating (EC).Conventionally this orientation is also given the flowing property of encapsulated particles 10 excellences, and they can unrestricted flow, and this is useful encapsulated particles 10 being applied to matrix in as ground process.In other embodiments, above-mentioned relative concentration is changed direction in nuclear particle 12, and making concentration gradient is reverse (not shown).In other embodiment, layer of polyurethane 14 is homogeneous substantially, and layer of polyurethane 14 does not comprise concentration gradient (not shown) conventionally.The method that forms these concrete layer of polyurethane 14 will below be further described.

The isocyanate component of described reaction product and isocyanate-reactive component can be offered to human consumer to use by variety of way, for example, in railcar, tank car (tanker), large size rotary drum and container or reduced size rotary drum, handbag (tote) and packaging kit.For example rotary drum can contain isocyanate component and another rotary drum can contain isocyanate-reactive component.Each component is separately offered to the premature reaction that human consumer has reduced each component, and provide the formulation flexibility of improving the formulation flexibility that therefore improvement is provided for encapsulated particles 10 for forming reaction product.For example, human consumer can select concrete isocyanate component and concrete isocyanate-reactive component and consumption thereof, thereby prepares layer of polyurethane 14 by it.Also can use various nuclear particles 12.If use other components as assisted polyvalent alcohol and/or binder component as tinting material, these components can provide separately or provide with isocyanate component and isocyanate-reactive component one or both of premix.

For forming encapsulated particles 10, provide nuclear particle 12.Then isocyanate component and isocyanate-reactive component are applied on nuclear particle 12.During contact (and under reaction conditions of understanding in polyurethane field), isocyanate component and isocyanate-reactive component start reaction and are positioned at nuclear particle 12 layer of polyurethane 14 around to form, thereby form the particle 10 of sealing simultaneously.

In one embodiment, before isocyanate component is applied to nuclear particle 12, isocyanate-reactive component is applied on nuclear particle 12.As mentioned above and as shown in Figure 1, this embodiment is used to form concentration gradient, described concentration gradient has contiguous nuclear particle 12 (being for example positioned at around nuclear particle 12) to form the concentration of the isocyanate-reactive component of isocyanate-reactive layer, and wherein isocyanate component is positioned at this isocyanate-reactive layer around and reaction with it.In another embodiment, before isocyanate-reactive component is applied on nuclear particle 12, isocyanate component is applied on nuclear particle 12.As mentioned above, this embodiment is used to form concentration gradient, described concentration gradient has contiguous nuclear particle 12 (being for example positioned at around nuclear particle 12) to form the concentration of the isocyanate component of isocyanic ester layer, and wherein isocyanate-reactive component is positioned at this isocyanic ester layer around and reaction with it.

In one embodiment, by isocyanate component and isocyanate-reactive component premix to form mixture.Then this mixture is applied on nuclear particle 12 to form the particle 10 of sealing.As mentioned above, this embodiment is used to form homogeneous layer of polyurethane 14, and layer of polyurethane 14 does not have the concentration gradient described in above-mentioned embodiment substantially, but has the dispersed of the polymer beads 16 that spreads all in 14 layers of whole layer of polyurethane.

Can apply each component by the whole bag of tricks known in the art.For the present invention, suitable encapsulating method example comprises that body coating, tumble enamelling, sheet material coating, pan coating method (pan coating), fluidized bed coating process, coextrusion, spraying and rotating disk seal.These methods and other encapsulating methods are that the technician of urethane and field of chemical engineering is known.In certain embodiments, each component spraying, atomization and/or cloud, to nuclear particle 12, to nuclear particle 12, are stirred to nuclear particle 12 simultaneously conventionally in suitable equipment.Each component spraying, atomization and/or cloud are positioned to nuclear particle 12 homogeneous, complete and flawless layer of polyurethane 14 around to conventionally producing on nuclear particle 12.Each component spraying, atomization and/or cloudization are also produced and is positioned at nuclear particle 12 thinner and more cheap layer of polyurethane 14 around.Yet, can use if necessary some steps that apply to form the thickness of layer of polyurethane 14.The spraying of each component, atomization and cloudization can for example provide a nozzle of each component by using nozzle carry out to it, or by two or more component premixs the nozzle that provides to it.Common at least one nozzle is by isocyanate component, and at least one nozzle is applied to isocyanate-reactive component on nuclear particle 12.As described above and illustrative, can use difference to apply order to form layer of polyurethane 14.

For the covering of nuclear particle 12 is maximized, conventionally each component is sprayed by drop or the particle atomization of each component or cloud are applied on nuclear particle 12, nuclear particle 12 overturns in revolution mixing machine or similar devices simultaneously.As another example, can be equipped with at least one, conventionally in the tumbler mixer of at least two rotating disc type spraying guns, by each component, apply nuclear particle 12.As understood in the art, also can use cylinder, rotary drum or comprise the roller of baffle plate.Or, nuclear particle 12 directly can be offered to carrier as screen cloth travelling belt, and for example can each component be applied on nuclear particle 12 to form the particle 10 of sealing by spraying or compressing tablet.In addition, on nuclear particle 12, can exist at least one component as isocyanate-reactive component, make then all the other components of reaction product to be applied in nuclear particle 12 and isocyanate-reactive component to form layer of polyurethane 14 as isocyanate component.Before layer of polyurethane 14 fully solidifies, conventionally keep encapsulated particles 10 to move to avoid agglomeration.

The consumption of each component to be applied and that mix with nuclear particle 12 depends on some variablees, comprises the desired use of the size of concrete component used, nuclear particle used 12 and type, encapsulated particles 10, the performance of the thickness of required layer of polyurethane 14 and required encapsulated particles 10.

Encapsulated particles 10 can have different size and shape.Conventionally, it is approximately 7.5 millimeters of about 0.5-(mm) that encapsulated particles 10 is mean diameter substantially, is more typically the about 3mm of about 0.5-, is generally the spherical of the about 2mm of about 1-most; Yet encapsulated particles 10 also can be other shapes, for example, be irregular, scrotiform, ellipse or sheet encapsulated particles 10.

Be not subject to anyly specifically theoretical fetter or limit, it is believed that isocyanate-reactive component gives encapsulated particles 10 with water-repellancy to a certain degree.Particularly, the graft polyol that it is believed that layer of polyurethane 14 has been given this water-repellancy.A kind of method of being given water-repellancy by isocyanate-reactive component of the present invention is the surface that applies at least partly nuclear particle 12, reduces thus this surperficial surface tension.The other method of being given water-repellancy by isocyanate-reactive component is to make isocyanate-reactive component fill at least partly the kapillary in nuclear particle 12 and/or layer of polyurethane 14, and stopping that the kapillary of water is absorbed is provided thus.In addition, it is believed that isocyanate-reactive component reduced solidify or after fixing with the formation of micron and/or nanometer crackle in layer of polyurethane 14 in forming the process of encapsulated particles 10.In addition, if there are these crackles in nuclear particle 12, isocyanate-reactive component is filled these crackles at least partly, as above to mentioned in description capillaceous.It is believed that stopping with the filling of crackle of water reduced degradation problem, as store and treating processes in swelling and agglomeration when encapsulated particles 10 is exposed under atmospheric moisture.This has improved the storage time of encapsulated particles 10, and has improved for example, intensity and elasticity in transportation (shipping) and treating processes of encapsulated particles 10.Thisly stop and fill the dissolving of also controlling better encapsulated particles 10, as further discussed below.In addition, it is believed that the polymer beads 16 due to graft polyol, this " filling " occurred to a great extent.Particularly, the polymer beads 16 that it is believed that isocyanate-reactive component is filled these crackles (if present) at least partly.In certain embodiments, except filling crackle, polymer beads 16 also can react with isocyanate component, and this can improve intensity and the toughness of layer of polyurethane 14.Below other benefits of being brought by graft polyol will be further described.

As isocyanate component and isocyanate-reactive component described and illustrative, encapsulated particles 10 can be offered to human consumer in the identical mode of each component with being used to form them above.Conventionally with bag, as paper bag and/or plastics bag form containing the approximately 80 pounds of encapsulated particles 10 of 1-of having an appointment provide encapsulated particles 10, process and apply being easy to.It will also be appreciated that except the particle 10 of sealing, described bag also can comprise other nutrition and/or filler, those as conventionally comprised together with conventional fertilizer.In certain embodiments, described bag can comprise seal with non-encapsulated particle the two.It will also be appreciated that described bag can comprise the encapsulated particles 10 of different grades, as there are different dissolution rate those (these can be given by different layer of polyurethane 14 thickness).

It should be understood that and various encapsulated particles 10 can be offered to human consumer with form of mixtures, as there is the encapsulated particles 10 of different IPs particle 12 (such as different types of fertilizer as nitrogen and potash, nitrogen and sulphur etc.).Encapsulated particles 10 also can have different physical propertiess, such as different size and dimensions, different dissolution rate, different hardness etc.These character will below described.Encapsulated particles 10 not agglomeration conventionally, make encapsulated particles 10 dumpable to easily use, and it can unrestricted flow, and therefore do not block the equipment that is used for providing and/or being coated with (for example, by using fertilizer spreader) encapsulated particles 10.

Depend on and comprise concrete component used and consumption, the size and dimension of nuclear particle 12, some variablees of the thickness of the size and dimension of encapsulated particles 10 and layer of polyurethane 14, encapsulated particles 10 can have different hardness (or " crushing " intensity).For the encapsulated particles of prior art, encapsulated particles 10 has excellent hardness conventionally.The hardness of encapsulated particles 10 provides the life-span of longer encapsulated particles 10, makes encapsulated particles 10 have excellent processing and storage/storage life.Particularly, layer of polyurethane 14 of the present invention provides the elasticity of the encapsulated particles 10 of raising for conventional encapsulated particles.The polymer beads 16 that it is believed that layer of polyurethane 14 provides this elasticity by playing the effect of the buffering/shock absorbent of encapsulated particles 10.Encapsulated particles 10 had conventionally at least about 1 month, more generally at least about 5 months, the most conventionally at least about storage time of 10 months.Should be understood that, the encapsulated particles 10 of part based on humidity exposure (or lack) can have the unlimited storage time of being close to, and is more typically 20 years or more for many years.

The mode discharging when encapsulated particles 10 of the present invention also can be used for selecting provides nuclear particle 12, as fertilizer.While selecting, discharge, be that layer of polyurethane 14 perforation are so that nuclear particle 12 can be released into the time required in surrounding environment, depend on some variablees, comprise the size and dimension of concrete component used and consumption thereof, nuclear particle 12, the thickness of the size and dimension of encapsulated particles 10, layer of polyurethane 14.This mensuration can be easily by encapsulated particles 10 is placed in to water-filled beaker so that complete awash test of encapsulated particles 10.The perforation of layer of polyurethane 14 can be passed through visual inspection encapsulated particles 10, and/or assesses by observing the variation of water clarity.Perforation can be by the pin hole of layer of polyurethane 14 or the extension that comes off.Should be understood that, only in the situation that layer of polyurethane 14 is sealed nuclear particle 12 completely, just discharge during applicable selecting; Otherwise, nuclear particle 12 is at least exposed in surrounding environment.

During the selecting of encapsulated particles 10, discharge also relevant with the dissolution rate of encapsulated particles 10 as above.As understood in the art, dissolution rate is the tolerance that nuclear particle 12 is dispersed to the amount in surrounding environment, for example, when encapsulated particles 10 is exposed in moisture (for example, from rainwater or irrigation), is released in time the amount of the fertilizer in surrounding soil.Encapsulated particles 10 has the excellent dissolution rate with respect to the encapsulated particles of prior art, this can with reference to Fig. 2,3 and 4 and embodiment below partly understand.Encapsulated particles 10 of the present invention has uniform dissolution rate conventionally, and nuclear particle 12 discharges to intimate stable state within for some time.Or or extra, encapsulated particles 10 of the present invention has slow release effect, thus for example encapsulated particles 10 be first exposed under enough moistures, infiltrate layer of polyurethane 14 after for some time, nuclear particle 12 starts to dissolve and therefore discharge.

A kind of mode that this dissolving is worked is that layer of polyurethane 14 is permeated, thereby water can be entered in encapsulated particles 10.After water enters, water can be with nuclear particle 12 as fertilizer interaction.For example, if nuclear particle 12 comprises nitrogen base manure material, in water migration by after layer of polyurethane 14, nitrogen base manure material is dissolved in the solution of encapsulated particles 10 inside, described solution then move by layer of polyurethane 14 in surrounding soil with delivery of nitrogen.When nuclear particle 12 is fertilizer, water and/or other liquid conventionally can not too fast infiltration layer of polyurethane 14, and anti-sealing and/or other liquid dissolve nuclear particle 12 fast thus, thus the phytotoxicity of preventing more measurable and controlled dissolution rate is provided.

Following examples of elaboration encapsulated particles of the present invention are intended to set forth the present invention but not are limited.

Embodiment

In beaker, prepare encapsulated particles.First by isocyanate-reactive component, be particularly polyvalent alcohol, heat and drop to and contain nuclear particle, particularly in the beaker of urea spheres (being fertilizer) to form polyvalent alcohol-urea admixture.Use foams mix blade that polyvalent alcohol-urea admixture gentleness is turned round and round to guarantee that polyvalent alcohol is distributed in around urea spheres.Then, isocyanate component heated and add in this polyvalent alcohol-urea admixture, manually turning round and round to guarantee to contact completely between urea spheres and polyvalent alcohol and the reaction product of isocyanate component.Contact produces and is positioned at urea spheres layer of polyurethane around completely.Subsequently with foams mix blade stir be coated with reaction product urea spheres so that agglomeration minimize, thereby produce encapsulated particles, the unrestricted flow group of the urea spheres of sealing.

Generally, the amount that to take based on urea gross weight be 2 % by weight and 4 % by weight applies layer of polyurethane and changes to measure by thickness the difference being caused.This difference is shown in following table 1-3.All layer of polyurethane (or coating) are with based on reactive site, i.e. NCO: OH functional group is 1.1: 1 (isocyanic ester: polyvalent alcohol) ratio applies.Some comparative examples lack one or more said components, as shown in following table 1 and 2.All embodiment are all used urea and the isocyanate component of identical type, and it will below described in further detail.

Carry out shaker test to measure the dissolution rate of each encapsulated particles.Described particle is placed in to the bottom of thick fraction sintered glass funnel.Urea discharges by measuring for 5 times with 500ml cold running water washing 15g particle.During each washing, will pour in funnel fast corresponding to the water of about 5.08cm (2 inches) rainwater.Make water in " self speed " lower filtration encapsulated particles of action of gravity, and do not apply any suction.Collect filtrate (or elutant) and be placed in sample bottle.Use standard method of analysis to analyze the urea content of elutant sample.The dissolution rate of each particle the results are shown in following table 1-3.

Table 1

" nuclear particle " is the pure urea granules without any coating.Herein, in all embodiment, all use identical urea, and be the urea of the conventional grade that can be obtained by a plurality of suppliers.As above and as shown in Fig. 2, urea (uncoated) substantially in washing for the first time by whole wash-outs, this confirms that for measuring the method for grain dissolution speed be effective.

" isocyanate composition " is for only having the urea granules of the coating of 2 % by weight isocyanate components.Described isocyanate component is that functionality is approximately 2.7, NOC content is that viscosity at 31.5 and 25 ℃ is the polymerization methylenediphenyl diisocyanates (pMDI) of 200mPas (centipoise).Isocyanate component can be with trade(brand)name m20S is by BASF Corporation of FlorhamPark, and NJ is commercially available.In all embodiment of the present invention, all use identical isocyanate component (except nuclear particle).As above, with as shown in Fig. 2, urea is quick wash-out in front twice washing, and this shows that independent isocyanate component can not provide enough protections for urea spheres.

" comparative example 1 " is for having the urea granules of 2 and 4 isocyanate components of % by weight and the coating of polyol reaction product.Described polyvalent alcohol is Viscotrol C and has 162 hydroxyl value and 3 nominal functionality.As above, with as shown in Fig. 3, can learn the dissolution rate of comparative example 1.

Table 2

" comparative example 2 " is for having the urea granules of 2 and 4 isocyanate components of % by weight and the coating of polyol reaction product.Described polyvalent alcohol is the propoxylation polyvalent alcohol that causes of glycerine and the hydroxyl value with 388-408,3 nominal functionality and at 25 ℃, is the viscosity of 360mPas (centipoise).Described polyvalent alcohol can be with trade(brand)name gP430 is commercially available by BASF Corporation.As above, with as shown in Fig. 3, can learn the dissolution rate of comparative example 2."-" represents elutant not collect data.

" comparative example 3 " is for having the urea granules of the isocyanate component of 2 % by weight and the coating of polyol reaction product.Described polyvalent alcohol is the propoxylation polyvalent alcohol that causes of glycerine and the hydroxyl value with 222-237,3 nominal functionality and at 25 ℃, is the viscosity of 270mPas (centipoise).Described polyvalent alcohol can be with trade(brand)name gP730 is commercially available by BASF Corporation.As above, with as shown in Fig. 3, can learn the dissolution rate of comparative example 3.

" comparative example 4 " is for having the urea granules of the isocyanate component of 4 % by weight and the coating of polyol reaction product.Described polyvalent alcohol is for by ah aromatic amihe-based initiator and comprise propylene oxide (PO) and the derivative polyvalent alcohol of ethylene oxide (EO), and it has 390 hydroxyl value, 4 nominal functionality and at 25 ℃, is 10, the viscosity of 500mPas (centipoise).Described polyvalent alcohol can be with trade(brand)name p824 is commercially available by BASF Corporation.As above, with as shown in Fig. 3, can learn the dissolution rate of comparative example 4.

Table 3

" the present invention 1 " is for having the urea granules of 2 and 4 isocyanate components of % by weight and the coating of polyol reaction product.Described polyvalent alcohol be comprise Viscotrol C as external phase and SAN particle the graft polyol as polymer beads.For reproducible object, under 2 % by weight, carry out twice test.As above, with as shown in Fig. 4, learnt the present invention 1 dissolution rate.

" the present invention 2 " are for having the urea granules of 2 and 4 isocyanate components of % by weight and the coating of polyol reaction product.Described polyvalent alcohol is that hydroxyl value is 27-31, nominal functionality be 3 and the viscosity at 25 ℃ be the graft polyether trivalent alcohol of the secondary hydroxyl end-blocking of 4,340mPas (centipoise).Described graft polyol comprises that 44 % by weight SAN particles are as polymer beads.Described graft polyol can be with trade(brand)name 4600 is commercial by BASF Corporation.As above, with as shown in Fig. 4, can learn the present invention 2 dissolution rate."-" represents elutant not collect data.

Encapsulated particles of the present invention has more uniform dissolution rate for comparative example particle conventionally.Although some points of the dissolution rate of the embodiment of the present invention may exist fluctuation, it is believed that this is that this obstruction has extended the duration of contact of each washing greatly because the obstruction in strainer causes, thereby improved existing urea amount in corresponding elutant.In addition, encapsulated particles of the present invention has the higher resistance to elasticity of breaking conventionally for comparative example particle.

Described in an exemplary fashion the present invention herein, should be understood that, term used be intended to descriptive wording, and non-limiting wording.According to instruction above, can carry out many improvement and variation to the present invention.Can implement the present invention to be different from the mode specifically describing within the scope of claims.

Claims

1. a particle of sealing, it comprises:

Nuclear particle; With

Be positioned at around described nuclear particle and the layer of polyurethane of the reaction product that comprises following component:

Isocyanate component, and

The isocyanate-reactive component that comprises the graft polyol with external phase and polymer beads, its

Described in graft polyol be selected from polymer polyatomic alcohol;

The reaction product that wherein said polymer beads comprises styrene monomer.

2. according to the particle of sealing of claim 1, wherein said isocyanate component is selected from polymerization diphenylmethane diisocyanate, '-diphenylmethane diisocyanate and combination thereof.

3. according to the particle of sealing of claim 1, wherein said nuclear particle comprises fertilizer.

4. according to the particle of sealing of claim 2, wherein said nuclear particle comprises fertilizer.

5. according to the particle of sealing of claim 1, wherein:

Described nuclear particle comprises fertilizer,

Described isocyanate component is selected from polymerization diphenylmethane diisocyanate, '-diphenylmethane diisocyanate and combination thereof, and

Described isocyanate-reactive component comprises the polymer polyatomic alcohol with external phase and polymer beads, and wherein said external phase comprises the polyvalent alcohol with at least two hydroxy functional groups.

6. according to the particle of sealing of any one in claim 1-5, wherein said polymer beads comprises styrene acrylonitrile copolymer.

7. according to the particle of sealing of any one in claim 1-5, the amount that it is 5-70 weight part that wherein said polymer beads be take based on isocyanate-reactive component described in 100 weight parts is present in described isocyanate-reactive component.

8. according to the particle of sealing of any one in claim 1-5, wherein said external phase comprises the hydrophobicity polyvalent alcohol with at least two hydroxy functional groups.

9. according to the particle of sealing of claim 6, wherein said external phase comprises the hydrophobicity polyvalent alcohol with at least two hydroxy functional groups.

10. according to the particle of sealing of claim 7, wherein said external phase comprises the hydrophobicity polyvalent alcohol with at least two hydroxy functional groups.

11. according to the particle of sealing of any one in claim 1-5, and wherein said external phase comprises Viscotrol C.

12. according to the particle of sealing of any one in claim 1-5, and the mean thickness of wherein said layer of polyurethane is 50-200 micron.

13. according to the particle of sealing of any one in claim 1-5, has following concentration gradient in wherein said layer of polyurethane:

I) innermost layer partly mainly comprises isocyanate-reactive component and outermost layer and partly mainly comprises the concentration gradient of isocyanate component; Or

II) innermost layer partly mainly comprises isocyanate component and outermost layer and partly mainly comprises the concentration gradient of isocyanate-reactive component.

The method of the particle that 14. 1 kinds of formation is sealed, described method comprises the steps:

Nuclear particle is provided;

Isocyanate component and the isocyanate-reactive component that comprises the graft polyol with external phase and polymer beads are applied on described nuclear particle; With

Make described isocyanate component and isocyanate-reactive component reaction be positioned at described nuclear particle layer of polyurethane around to form, thus the particle of sealing described in forming, and wherein said graft polyol is selected from polymer polyatomic alcohol;

The reaction product that wherein comprises styrene monomer as the polymer polyatomic alcohol of polymer beads.

15. according to the method for claim 14, I wherein) before isocyanate component is applied on nuclear particle, isocyanate-reactive component is applied on nuclear particle, or II wherein) before isocyanate-reactive component is applied on nuclear particle, isocyanate component is applied on nuclear particle.

16. according to the method for claims 14 or 15, wherein:

Described nuclear particle comprises fertilizer,